The Burnt World of Athas - 30 Days of Dark Sun 21: What is your favorite psionic creature?

The 21st day of #30DaysofDarkSun is here and the question is "What is your favorite psionic creature?"

This is a companion discussion topic for the original entry at

Here I will pick the Id Fiend. It was a very fun creature in previous editions, was a superb level 1 solo in 4E, and the custom level 5 version I made was a ton of fun in my home campaign. I have the writeup of the session and the stats here.